Isis blitz Palmyra: Russian tanks and APCs were seized by Islamic State in a surprise advanceReuters

Islamic State (Isis) militants seized Russian arms including 30 tanks, large quantities of surface-to-surface Grad missiles, ammunition and tanks shells when they raided Palmyra, say observers. The extremists surprised Syrian forces, said to be have been part of a National Defence Force (NDF) unit of local fighters, on 10 December by retaking the symbolic city, famous for its ancient ruins.

During the sudden attack, the semi-trained militia crumbled as the terrorists advanced. With no protection from Russian troops, who had already fled Palmyra, the city fell.

In March 2016, Russian President Vladimir Putin, in a big show of force against global terrorism, hailed victory over Isis after seizing the territory and holding a concert at the ruins that Isis had partly destroyed.

Now, according to the UK-based Syrian Observatory for Human Rights (SOHR), Isis are in possession of a much-boosted arsenal left behind by the Russians.

Palmyra, known for its 2,000-year-old ruins, became the scene of fierce fighting on 10-11 December when a National Defence Force (NDF) unit of local fighters fought back with the aid of Russian airstrikes. Russian forces launched 64 strikes against the insurgents, which seemed to be successful in provoking a retreat.

Yet Isis reinforcements, who Russian officials said had escaped the embattled Iraqi city of Mosul, managed to seize back control of Palmyra. Footage from an Isis-affiliated news agency, Amaq, reportedly shows Isis forces standing next to abandoned Russian tanks and armoured personnel carriers at security checkpoints.

A view shows the Monumental Arch in the historical city of Palmyra, Syria, August 5, 2010.Reuters/Sandra Auger

It has now been reported that Isis militants are heading west towards the Tiyas airbase T4, located approximately 100km from Homs and 60km from Palmyra, which is used by Russian troops. Amaq also stated that the extremists took control of nearby oil and gas fields.

The ancient city was seized by Isis forces in May 2015, who murdered the city's 81-year-old director of antiquities, Khaled al-Asaad, and imposed their strict interpretation of Sharia law. The latest entry into Palmyra follows a three-day offensive which began on 8 December.

Militants from the Islamic State (Isis) celebrate after retaking Palmyra, Syria.Isis propaganda image